import java.net.InetAddress;
import java.net.UnknownHostException;

import javax.servlet.http.HttpServletRequest;

/**
 * @author Arnold Yand
 * @since Nov 2, 201710:00:09 AM
 * @summary .Demo.java
 */
public class Demo {
  public String getIpAddr(HttpServletRequest request) {
    
    String ipAddress = request.getHeader("x-forwarded-for");
    
    if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
      ipAddress = request.getHeader("Proxy-Client-IP");
    }
    
    if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
      ipAddress = request.getHeader("WL-Proxy-Client-IP");
    }
    
    if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
      ipAddress = request.getRemoteAddr();
      if (ipAddress.equals("127.0.0.1") || ipAddress.equals("0:0:0:0:0:0:0:1")) {
        // 根据网卡取本机配置的IP
        InetAddress inet = null;
        try {
          inet = InetAddress.getLocalHost();
        } catch (UnknownHostException e) {
          e.printStackTrace();
        }
        ipAddress = inet.getHostAddress();
      }
    }
    
    // 对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割
    if ( ipAddress != null && ipAddress.indexOf(",") > 0 ) {
      ipAddress = ipAddress.substring(0, ipAddress.indexOf(","));
    }
    
    return ipAddress;
  }
}
